We used an app to implement our Google Analytics code in order to add some extra functionality. It would appear that this "analytics on steroids" app inadvertently started tracking Google Analytics data three times instead of the one - there are three gifs on each page, and that would account for the absurdly low bounce rate.
The "Conversion" code for downloads is akin to the Ecom conversion code, it's just on your "thanks for downloading" receipt page, not on every page of the website.
Your app does complicate the troubleshooting here though, suggest you have them troubleshoot. If by gif, you mean they are pixel based, then sure, triple counting visits would lower your bounce rate and your other subsequent action tracking, like conversion rate.